Flame retardant flexible polyurethane foams

ABSTRACT

LOW DENSITY, FLEXIBLE AND SEMIFLEXIBLE POLYETHERURETHANE FOAMS CONTAINING HALOGEN-CONTAINING POLYMERS SUCH AS POLYVINYL CHLORIDE ARE RENDERED RESISTANT TO FLAME TO THE POINT OF BEING SELF-EXTINGUISHING BY THE USE OF MINOR AMOUNTS OF ALUMINA TRIHYDRATE AND ANTIMONY TRIOXIDE PART OF THE HALOGEN-CONTAINING POLYMER MAY BE REPLACED WITH A CHLORINATED PARAFFIN.

, 3,810,851 Patented May 14, 1974 ABSTRACT OF THE DISCLOSURE Low density, flexible and semiflexible polyetherurethane foams containing halogen-containing polymers such as polyvinyl chloride are rendered resistant to flame to the point of being self-extinguishing by the use of minor amounts of alumina trihydrate and antimony trioxide. Part of the halogen-containing polymer maybe replaced with a chlorinated parafiin.

CROSSYREFERENCE TO RELATED I APPLICATION This application is ia continuation-in-part of U.S. patept application Ser. No. 248,502, filed Apr. 28. 1972 and now abandoned.

BACKGROUND OF THE INVENTION Flexible and. semiflexible polyurethane foams have fonnd.-widespread utility in the fields of insulation, structural reinforcement,cushioning and electrical encapsulation. One factor limiting the commercial utilization of such foams has been their flammability when exposed to-fi'ame or high temperatures. The use of a combination of anti mony oxide and finely-divided vinyl halide resin is specifically shown in US. Pat. No. 3,075,928. Flame retardant polyurethane foams containing zinc oxide; polyvinyl chloride and antimony trioxi'de are disclosed in US. Pat. No.

3,574,149uF1am'e retardant polyurethane foams contain-' ing a mixture of alumina trihydrate and a chlorinated organic'phosphate are disclosed in U.S Pat. No. 3,262,

894?"Tl'1i's1ast patent states that by itselflthe alumina trihydrate d'oesfnotpro'vide a self-extinguishing fam, and.

itffails to disclose zinc oxide, antimony trioxide or polyvinyl chlcirideQ fv V v Accordingly, it is the primary object of this invention toprovide flexible and semiflexible, low density polyetherurethane foams which contain halogen-containing. polymers and; which have the property of flame-resistanceeven to the point of being self-extinguishing. It is a further object to provide a method for making such foams by the use of a simple but novel combination of additives.

These and other objects and advantages of the present invention will become more apparent to those'skilled in the art from the following detailed description and examples. v

SUMMARY OF THE INVENTION According to the present invention it has now been discovered that flexible and semiflexible polyetherurethane foamsare rendered not only flame-resistant but" also self extinguishing by incorporating into the foam composition, prior to the'blowing thereof into a foam, alumina" trihydrate .(Al' O .-.3H O or:2Al(OH) and'antimony trioxidetogether with a finely-divided halogen-containingsolid polymer. Partof the halogen containing polymer canbe replaced with a chlorinated paraflin.

U i d States P m vomce OF DETAILS AND PREFERRED EMBODIMENTS DESCRIPTION from about 30 to 80 parts, preferably about to 75 parts,

of alumina trihydrate and from about 1 to 20 parts, preferably about 3 to 15 parts, of antimony trioxide (Sb O The'halog'en containing solid polymers employed herein include polymers, usually resinous in character, of vinyl chloride, vinyl bromide, vinyl fluoride and vinylidene chloride and mixtures of these monomers as well as copolymers of a'predominating molar amount of one or more of these monomers and a minor amount of vinyl acetate, acrylonitrile, 'methacrylonitrile, dimethyl or diethyl maleate or furnarate, methyl acrylate, methyl methacrylate, ethyl ethacrylate, vinyl stearate and the like and mixtures thereof. Still other halogen-containing resins can be used such as hydrolyzed or partially hydrolyzed copolymers of a major amount of the vinyl -halide and a minor amount of vinyl acetate. Moreover, other resinous polymers can be used such as chlorinated rubber, chlorinated polyethylene, chlorinated polyvinyl chloride, polytetrafluoroethyl-- ene and the like. Mixtures of the halogen-containing polymeric resins can be used.

These halogen-containing resins should be finely divided (powders having average particle sizes of from about 0.00001 to 1 mm.) and have an intrinsic viscosity of from about 0.25 to 2.5, preferably from about 0.5 to 1.5. The,

halogen-containing resinous polymers are generally used inan amount of from about 2 to 100 parts by weight per 100 parts by weight of the polyol to obtain the desired load bearing"characteristics, but in many instances there need'be'only'about 5 to parts, preferably from about 15 to 35 parts by weight. The larger particle size resins can be used in larger amounts within the given ranges. However, the finer or smaller particle size resins should be used in smaller amounts within the ranges shown to avoid the formationof viscous, difficult .to pump or stir, fluids, gels or pastes. The halogen-containing polymers can be made by bulk, solvent, emulsion or suspension polymerization process. A preferred polymer to use is'poly vinyl chloride.

Part of the halogen-containing resin used in the foam. formulation can be replaced with a chlorinated paraffin or with mixtures of chlorinated paraffins. These materials are made by the chlorination .of liquid paraffin fractions and/or paraflin waxes. The chlorinated paraflins. have average molecular weights of from about 250 to 1400 and chlorine contents of from about 40 to by weight. They can be liquids or solids; preferably the liquid chlorinated paraflins are employed in the practice of the present invention. Also, it is preferred that the chlorinated paraffins be odor-free or substantially odor-free. Examples of chlorinated paraffins are the Cereclor (I.C.I. .America, Inc.) chlorinated parafiins Nos; 42, S. 45, S. 52, 'and'70', and the Chlorowax (Diamond Shamrock Chemical Com pany) chlorinated paratfins Nos. 40, 50 and 70. "Still other chlorinated paraffins can be used. From about Ste 70% by weight of the chlorinated paraflincan 'beused to replace an equal amount. by weight of h o ging polymer. I

The alumina trihydrate "should be finely divided, for

example, it should have an average particle size of from about 0.1. to 200 microns, preferably from about 1 to' 50' microns. While it may berefined or unrefined, it should not contain any appreciable amount of impurities which would adversely affect thefoaming reaction or the properties ofthe resulting foams.

The antimony trioxide, also, should be finely divided,

to 50 microns. It should not contain any deleterious materials which would adversely affect the foaming reaction or the properties of the resulting foam. The smaller particle sizes of antimony trioxide are most effective in the foam.

Polyols used in making the polyurethanes of the present invention are primary and secondary hydroxy-terminated polyoxyalkylene ethers having from 2 to 4 hydroxyl groups and a molecular weight of from about 1,000 to 10,000. They are liquids or are capable of being liquefied or melted for handling in the polyurethane foaming apparatus or machine.

Examples of polyoxyalkylene polyols include linear and branched polyethers having a plurality of ether linkages and containing at least two hydroxyl groups and being substantially free from functional groups other than hydroxyl groups. Among the polyoxyalkylene polyols which are useful in the practice of this invention are the polyethylene glycols, the polypropylene glycols, and polybutylene ether glycols. Polymers and copolymers of polyoxyalkylene polyols are also adaptable in the process of this invention as well as the block copolymers of ethylene oxide and propylene oxide. Among the copolymers of polyoxyalkylene polyols that deserve some special mention are the ethylene oxide, propylene oxide and butylene oxide adducts of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, 2-ethy1- hexanediol-1,3, glycerol, 1,2,6-hexanetriol, trimethylolpropane, trimethylolethane, tris(hydroxyphenyl) propane, triethanolamine, triisopropanolamine, ethylenediamine, and ethanolamine. Linear and branched copolyethers of ethylene oxide and propylene oxide are also useful in making the foamed products of this invention as well as those endblocked with ethylene oxide to provide primary hydroxyl groups in the polymer and having molecular weights of from about 2000 to 5000.

Further useful types of polyetherpolyols are block copolymers prepared from propylene oxide and ethylene oxide. These polyethers can be characterized by reference to the following general formulae:

where in Formula A the total of subscripts, x, y, and 2 represent positive integers in the range of from to 70 and the total of subscripts a and b of Formula B represent positive integers in the range of from 20 to 100.

. Polyetherpolyols having a branched chain network are also useful. Such branched chain polyethers are readily prepared from alkylene oxides of the type above described and initiators having a functionality greater than two. Branched polyethers have the advantage of making possible cross linking without the interaction or urea or ure-' thane groups with the isocyanate groups. This has the advantage of making a larger proportion of the isocyanate used available for the evolution of carbon dioxide and the reducing of the overall amount of isocyanate that is required in the preparation of the foamed 4 p t Likewise, there can be used as polyols grafts of ethylenically unsaturated monomers such as acrylonitrile, meth;

acrylonitrile, vinyl acetate, methyl acrylate and the like on the polyols and having the functionality and molecular weight as shown above. Such graft polyols and methods for making the same are shown in the U.S. patents to Stamberger, Nos. 3,304,273 and 3,383,351 and in the U.S. patent to Von Bonin, No. 3,294,711.

When desired, cross-linking materials having frorn2 to 8 hydroxyl groups can be included in the foam formulation to increase crosslink density and so forth. They have molecular weights of from about 60 to 600. Only small amounts of such materials are generally needed (about 0.3 to 10 mols per mols of polyol). Examples of such crosslinking agents are glycol, diethylene glycol, propylene glycol, butane diol-1,4, dipropylene glycol, trimethylolpropane, butane triols, hexanetriols, trimethylolphenol, tris(hydroxyphenyDpropane, tris(hydroxyxylyl)propane, various tetrols, such as erythritol and pentaerythritol, pentols, hexols, such as dipentaerythritol and sorbitol, as well as alkyl glucosides, carbohydrates, polyhydroxy fatty acid esters such as castor'oil and poly-v oxy alkylated derivatives of poly-functional compounds having three or more reactive hydrogen atoms, such as, for example, the reaction product of trimethylolpropane, glycerol, 1,2,6-hexanetriol, sorbitol and other polyols with ethylene oxide, propylene oxide, or other alkylene epoxides or copolymers thereof, e.g., copolymers of ethylene and propylene oxides. Grafted crosslinkers can be prepared by the process of the aforementioned Stamberger and Von Bonin U.S. patents. Mixtures of crosslinkers can be used. All the polymer-forming ingredients should preferably be free of any amine function which is not sterically hindered or shielded.

Any organic dior tri-isocyanate can be used in the practice of the present invention. Diisocyanates are preferred, particularly when there is any considerable amount of branching in the polyol or crosslinker to avoid the formation of rigid or semi-rigid foams and vice versa. Exaniples of suitable organic polyisocyanates to use are ethylene diisocyanate, trimethylene diisocyanate, tetra- 2,4-tolylene diisocyante, 2,6-tolylene diisocyanate, bitolylene diisocyanate, naphthalene-1,4-diisocyanate, and diphenylene-4,4'-diisocyanate; aliphatic-aromatic diisocyanates such as xylylene-1,4-diisocyanate, xylyene-1,3-diisocyanate, bis(4-isocyanatophenyl) methane, bis(3-methyl- 4-isocyanatophenyl)methane, and 4,4'-diphenylpropane diisocyanate, durylene diisocyanate, 4,4',4"-tris(isocyanatophenyl) methane, 3,1O-diisocyanatotricyclo[5.2.1.0 decane, bis-(2-isocyanatoethyl) carbonate, and naphthalene triisocyanate and the like. Mixtures of polyisocyanates can be used.

The polyisocyanate is used in an amount sufiicient to react with the active hydrogen atoms (as determined by the Zerewitinotf method, J.A.C.S., vol. 49, p. 3181 (1927)) in the polyols, crosslinkers, water, halogen-containing resins (such as partially hydrolzed vinyl chloridevinyl acetate copolymers) and any other active hydrogencontaining material in the polyurethane foam formulation to provide the desired degree of crosslinking, chain extension, urea groups, blowing and so forth to obtain the desired flexibility, strength and other physical properties.

Water is used as a blowing agent and is employed in amounts of from. about 1.0 to 5.5 parts by weight per 100 parts by weight of the polyol.

The Water should be substantially or essentially pure, that is, it should be free of impurities such as ions, sols, etc. of mineral, vegetable or synthetic origin and the like which would adversely aifect the foaming action or the properties of the resultant polyurethane foam. Deionized, distilled or otherwise purified water should be employed.

It lower density and softer foams are desired there additionally can be added to the polyurethane foam formulation separately or in admixture with one of the other components, i.e., polyol or polyisocyanate, etc., up to about 25 parts by weight of a fluorocarbon blowing agent per 100 parts by weight of the polyol. Examples of such blowing agents are those fluorine substituted aliphatic hydrocarbons which have boiling points between about --40 C. and +170 C., and which vaporize at or below the temperature of the foaming mass. The blowing agents include, for example, trichloromonofiuoromethane, dichlorodifluoromethane, dichloromonofiuoromethane, bromotrifluoromethane, chlorodifluoromethane, 1,1-dichloro-l-fluoroethane, 1,1-difluoro-1,2,2-trichloroethane, chloropentafluoroethane, l-chloro-l-fiuoroethane, 1-chloro-2- fluoroethane, 1,1,2-trichloro-l,2,2-trifluoroethane, 1, 1,1- trichloro 2,2,2 trifluoroethane, 2-chloro nona fluorobutane, hexafluorocyclobutene, and octalluorocyclobutane. Still other easily 'vaporizable fluorocarbons can be used. Mixtures of the fluorocarbons can be used; Still other blowing agents can be used in full or partial replacement of the tfluorocarbons such as propane,'butane, pentane, pentene, hexane and so forth, and mixtures thereof, particularly where precautions are taken to prevent explosions or where removal of the gasses is provided. See US. Pats. Nos. 3,072,582 and 3,391,093.

Catalysts for the polyetherpolyol-polyisocyanate reaction can be any catalyst heretofore used in the art particularly the metal-containing catalysts. Examples of such catalysts are 1') tertiary phosphines such as trialkylphos-' phines, dialkyl-benzylphosphines, and the like; (2) strong bases such as the alkali and alkaline earth metal hydroxides, alkoxides, and phenoxides; (3) acidic metal salts of strong acids such as ferric chloride, stannic chloride, stannous chloride, antimony trichloride, bismuth nitrate, bismuth chloride, and the like; (4) chelates of various metals such as those which can be obtained from acetylacetone, benzoylacetone, trifiuoroacetylacetone, ethyl acetoacetate, salicylaldehyde, cyclopentanone-Z-carboxylate, and the like, with various metals such as Be, Mg, Zn, Cd, P'b, Ti, Zr, Sn, As, Bi, Cr, Mo, Mn, Fe, Co, Ni, or ions such as M and the like; (5) alcoholates and phenolatesof various metals such as Ti(OR) Sn(OR) Sn(OR) Al(OR) and the like, wherein R is alkyl or aryl, andthe reaction products of alcoholateswith carboxylic acids, beta-diketones and 2-(N,N-dialkylamino) alkanols, such Sn, Pb, Mn, Co, Ni, and Cu, including, for example, sodiumacetate, potassium laurate, calcium hexanoate, stan-h,

nous acetate, stannous octoate, stannous oleate, lead octoate, metallic driers such as manganese, cobalt, lead naph- (Z-methylaminopentylate), dibutyltin dichloride, dioctyltin dichloride, and the like and mixtures thereof. Preferred catalyts to use are the divalent tin salts of carboxylic acids having from 2 to 18 carbon atoms. These catalysts are used in an amount of from about 0.1 to 0.9 part by weight per 100 parts by weight of the polyctherpolyol. It is less preferable to use these catalysts, such as the metal salts, alcoholates, hydroxides, alkoxides and phosphines, especiallyvin large amounts, where resins containing ester groups in a substantial amount are used since they tend to hydrolyze the ester linkages thereby causing scission of the backbone polymer chain and loweringgof the physical and chemical properties of the resulting foams and so forth, especially under conditions of high temperature and humidity. 1

Surfactants or emulsifiers are generally necessary to provide the desired cell formation and growth. Polysiloxanepolyoxyalkylene block copolymers are preferred. Polysiloxane-polyoxyalkylene block copolymers are described in US. Pats. 2,834,748 and 2,917,480. Another useful class of emulsifiers are the non-hydrolyzable polysiloxane-polyoxyalkylene block copolymers. This class of compounds differs from the above-mentioned polysiloxauepolyoxyalkylene block copolymers in that the polysiloxane moiety is bonded to the p lyoxyalkylene moiety through direct carbon-to-silicon bonds, rather than. through carbon-to-oxygen-to-silicon bonds. These copolymers generally contain from 5 to 95 weight percent, and preferably from 5 to 50 weight percent, of polysiloxane polymer with the remainder being polyoxyalkylene polymer. The copolymers can be prepared, for example, by heating a mixture of (a) a polysiloxane polymer containing a siliconbonded, halogen-substituted monovalent hydrocarbon group and (b) an alkali metal salt of a polyoxyalkylene polymer to a temperature sufficient to cause the polysiloxane polymer and the salt to react to form the block copolymer. Still other polysiloxane-polyoxyalkylene copolymers known to the art may be employed as well as silicones, Turkey red oil and so forth. The surfactant is used in an amount of from about 0.3 to 2.5 parts by weight per 100 parts by weight of the polyether polyol.

It is advantageous to incorporate into the urethane compositions of the present invention at least one organic tertiary amine catalyst, preferably together with a metalcontaining co-catalyst. The amount of organic amine catalyst may comprise, per 100 parts by weight of organic polyol,yabout 0.05 to 3.2 parts by weight. In the case of the polyether' polyols where a metal catalyst is used for the urethane-forming reaction, it is preferred to use only from about 0.05 to 0.9 part by weight of the amine. On the other hand, where the tertiary amine is taking care of both the foaming (H 0+NCO) and network.

reactions, the tertiary amines should be used in somewhat larger amounts within the specified ranges. However, since some polyols may differ in residual acid content (from neutralization of KOH catalyst (used to form polyol) with thenate and the like; (7) organometallicderivatives of 1 tetravalent tin, trivalent and pentavalent As, Sb, and Bi,

and metal carbonyls of iron and cobalt; and (8) the dialkyltin salts of carboxylic acids, e.g., dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, dilauryltin diacetate, dioctyltin diacetate, dibutyltin-bis(4-methylaminobenzoate), dibutyltin bis(6 methylaminocaproate), and the like; as well as a trialkyltin hydroxide, dialkyltin oxide, dialkyltin, dialkoxide, or a dialkyltin dichloride, such as trimethyltin hydroxide, tributyltin hydroxide, trioctyltin hydroxide, dibutyltin oxide, dioctyltin oxide, dilauryltin oxide, dibutyltin-bis (isopropoxide), dibutyltin-bis acid) due to incomplete washing, filtering or ion-exchangmg of the neutralized polyol and since antimony trioxide has some catalytic effect during the polyurethane foaming and forming reactions, the amount of tertiary amine may necessarily have to be reduced where large amounts of water areused as the primary blowing agent.

In the urethane compositions of the invention there may be used a wide variety of organic tertiary amine catalysts. Suchorganic amines, include, among others, triethylene diamine, triphenyl amine, triethylamine, N,N,N',

'-tetramethyl-1,3-butanediamine, N-methyl morpholine, N-ethyl morpholine, N-acetyl morpholine, N-octyl morpholine, .N-coco morpholine, N-phenyl morpholine, N- hydroxyl ethyl morpholine, NrhYdI'OXYl methyl morpholine, 4,4-dithiodimorpholine, dimethyl piperazine, N,N,

N, -tetramethy1 propane diamine, trimethyl amino- 7 ethyl piperazine, N,N-dimethyl ethanolamine, dimethyl ,hexadecyla rnine, 1-(2aethyl-1-hexenyl) piperazine, tri noctaylamine, trimethylamine, N,N-dimethyl benzyl amine, triethanolamine, 1,2,4-trimethylpiperazine, N-methyl dicyclohexylamine, and mixtures thereof. The sterically Preparingthesame Using Certain Catalysts," issued Nov.

10,,1970, also, can be employed in the foam formulations if desired,. oth ei' well known constituents can be added to the polyurethane foam recipe such as barium and cadmium salts of carboxylic acids, clay, talc, TiO silica and hydrated silica, CaCO metal chromates, barytes, phthalocyanine green or .blue pigments, red iron oxide, conventioanl stabilizers,'carbon black, dyes, toners, extending oils, proc esfsing joils, epoxided soy bean oil (Paraplex 6-62),

'eppxides (Epon 828'), tricrsyl phosphate, plasticizers,

antioxidants, fungicides, bacteriostats, reodorants and the like. These constituents can be added in various amounts to. the foaming ingredients to achieve the desired properties in .the resultant flexible, low density foams.

The, flexible, cellular urethane-vinyl chloride polymeric foamsof the present invention can be used as cushions, mattresses, pillows, packing, cushioning material for furniture, automobiles, rug underlay, interior automobile and other vehicle door panels, seats, arm rests, head rests,

and so forth.

The preparation of the polyurethane foam of the present invention can be formed by a process known in the art as the one-shot process or by a two step process involving, first, the preparation of a prepolymer, the

the halogen-containing polymer to form a rubbery,, cellular, elastic product. v i No matter which particular technique is used, the halogen-containing polymer .or resin may not only be dispersed with the polyol alone, but alternatively with the organic polyisocyariate alone. Stillanother method within the purview of the present invention'involves dispersing the halogen-containing polymer with a combinationof the polyol and the organic polyisocyanate. In any case, it is advantageous to disperse the halogen-containingpoly mer 'thoroughly into whatever, particular initial compost tion is used. I v Y The following examples are intended to illustrate more fully but not to limit the invention which is properly delineated in the claims.

EXAMPLE I The polyol, polyvinylchloride, water, alumina trihy drate, antimony, trioxide, surfactant, amine catalysts and processing oil were mixed together to form a polyol blend. The blend was then thoroughly mixed with the tin cat'- alyst in DOP as a carrier and the tolylene diisocyanate and poured into a mold and allowed to foam for several minutes. After' this, the foam 'was placed in an ov en at 250 -F. and cured at this temperature for several'min utes. Similar foams were made in which the ingredients were varied and wherein antimony trioxide were omitted fromthe formulation. V

After curing and cooling, samples were cut from the foam and theywere given various tests to show their physical properties and resistance to flammability.

The ingredients of the foam formulations and the results obtained on testing the flexible foams are shown in the table below:

TABLE Run A B O D E F Foam ingredients, parts by weight: I

Poly (3-3030 PG 1 100.0 k 100. 0 100.0 100.0 100.0 100.0 2. 5 2. 5 2. 5 2.5 2. 5 2. 5 0 Z 0. 75 0. 75. 0. 75 0. 75 0. 75 0. 75 0.5 0.5 0.5 0.6 0.6 7 0.6 0.1 ,0.1 0.1- 0.1 0.1 0.1 Polycat. 12 0. 2 0.2 0. 2 0.2 0.2 0.2 Marvinol 51 20. 0 20. 0 20. 0' 30. 0 30.0 30.0 Alumina trihydrate 50.0 50. 0 50.0 70. 0 70.0 70. 0 Antimony trioxide 3.0 5. 0 3. 0 5. 0 Daet 5.0 5.0 5.0 5. 0 5.0 5'. 0 TDI 36.0 36.0 36.0 36.0 36.0 36.0 Foam properties:

Density (lbs/1L?) 3. 3. 3.55 4.00 4 10 4.10 Tensile strength (p.s.i.) 13.0 13.3 13.0 13.3 13.5 I 13. 2 Elongation (percent).-. 90 107 116 82 80 1 80 Tear strength (p.l.i.) 1.73 1.58" 1. 6 1.35 1. 28 1.48 Comp. load defL: I

25 38.8 38. 7 41. 46.2 46.2 100. 0 96. 2 126. 0 127. 5 126. 2 25% R 32. 5 31. 2, 32. 5 37. 5 37. 5 Compression set (percent) 9. 7 9.9 10.0 11. 4 11.8 Flammability (ASTM D- '0 Burns Initial rate (/min.) 0.6 0.4 0.7 0.5 After heat aging (/min.) (22 hrs. at 284 F. 1 5 0.25 0.25 0 6 0.75 Weight loss after heat aging percent) (22 hrs. at 284 3 0 0.35 0 3 0 4 0.36 0.35

I Propylene oxide adduet of glycerol, secondary hydroxyl tn'ol, 3,000 M.W., approximate analysis: OH-No. l 56.3, Acid No. 0.038, H10 0.018%, Olin Corporation. I

. 2 Polysiloxane-polyoxyalkylenc block copolymer, surfactant, Union Carbide. I

5 Stannous octoate in a carrier; 1 part of stannous oetoate in 2 to 4 parts of dioctyl phthalatc. The figure shown in the column is for the stannous octoate per se. I I

4 0(CH:CH2-N(CH3)2)2 in a carrier by weight 111 dipropylene glycol). The figure shown in the column is for the amine per se.

5 Methyl dicyclohexyl amine.

' Polyvinylchloride resin, average Naugatuck Chemical Division.

particlesize of 1.7 microns, 0.50 specific viscosity, plastis'ol grade, Uniroyal,

7 Finely divided, Alcoa (3-30 BD-A.

i Finely divided. Low viscosity, cell openin g, processing oil, Houdry Process Corporation /20 mixture 0124- and 2,6-tolylene,diisocyanates.

Self-extingmshing time sec. Self-extinguishing time 75 sec.

1! Self-extinguishing time 30 see. 14 Would not ignite. I

well known semiprepolymer or t uasi- 'prepolymer In the foregoing .AS TM -D -1692 68 test a Bunsen technique. There all or a portion of the polyolis reacted 70 burner flame having a blue cone of 1.5 inches in, height with all of the organic polyisocyanate, providing a reaction product which contains a high percentage freeisocyanate groups and which is reacted with the remaining portion of the hydroXyl-terminated polyol or across is, applied separately to the front edge of the foam test specimens (6 inches by-2 inches by 0.5 inch) and allowed to. remain incontact therewith for a period of sixty secends or until the one inch bench mark is reached. The

linker, together with water, catalysts, metal oxides and 5 self-extinguishing time is measured in seconds. and the 9 H distance burned is considered the furthermost point reached by the flame.

The above data clearly shows theiimprovement in flame resistance imparted to polyurethane foams containing a halogen-containing resin and antimony trioxide by the use of alumina trihydrate. Moreover, thewfoams containing thealumina trihydrate form a hard charatthe flame front to insulate the flame front from the material in back of the flame rather than melt; and drip hot burning material. Similar foams containing only polyvinylchloride (no sb o nor Agog-sum burned, for example, "they are not exhibit any, self-extinguishing, properties, when tested according to the foregoing test. 7

EXAMPLE II Additional polyurethane foams were, prepared by the method generally disclosed abovefand tested for; their selfextinguishing properties by a'modified test for mattress construction. The foam formulations were as follows.

1 "FOAM FORMULATION NO. 1 I

Ingredient: Parts byweight Voranol HR-5000 (Dow chemicalCoL, approximately 25% ethylene oxide and 75 propylene oxideadduct of.atriol,.about 4500 molecular weight, contains 1.7% bromine in" the form of an organic compound) LD-8 13 (Du PontCo, mixtureofmethylene bis-ortho chloro-aniline and meth ylene tris ortho chloro-aniline, functionality of about L H O, deionized A-l (see Example 1, above) N-e'thylmo'rpholine k 1 M DC20O silicone fiuid (Dow Corning Corp.,

K polydimethylsiloxanepil) Tolylene diisocyanate, 80/20, 2,4

FOAM FoRMULATlofiNol i *See Example I, above. 7 7

' FoAMroRMULAr1o No.3 .1 4 Ingredients: P 1

Poly o-sosoro A1* i TT9* Y 0.40 2 r 9 l ."-.'."1 .1 Tolylene diisocyanate ado/20, 2, d v 52.0 Polyvinylchloride resin .15

- Antimony; trioxide, finely divided Zinc oxide, French process, finely v divided Geon 121, emulsion polymerizeddntrinsic viscosity-of about 1.28, 100% through 200 meshjless than about microns)- The B. F. Goodri'ch'Co.

*See Example I, above.

" FOAM FORMULATION NO. 4

Ingredient; v Parts by weight Poly (34.030 PG* 100.0 L-540* 0.8

Triethylene diamine (DABCO, Houdry Proc- Triethylene diamine (Dabco, Houdry Process Corporation) 0.24 Dactol* 5.0 H 0, deionized 2.2 Freonll, C13FC (Du Pont) 11.0 Alumina trihydrate, finely divided 1 50.0 Antimony trioxide, finely divided 5.0 I Polyvinyl chloride resin 30.0 f 'Tolylene diisocyanate, 80/20, 2,4-/2,6- 31.5

1 AlcoaC--BF, unrefined.

#Vygen 1 10, General Tire 8: Rubber Company, intrinsic viscosity 1.03, particle size range about 44449 microns, suspension polymerized.

*See Example I. above.

The ability'of the polyurethane foams to insulate cottonbatting from ignition by both burning cigarettes and methenamine tablets (11) was investigated. The test for this work-was as follows: 1 inch thick cotton batting was cut into 4" x 4" squares. Foam samples of desired thickness were also cut into 4" x 4" squares. Both cotton batting and foam samples were conditioned at least 48 hours at 70 F. and 50% relative humidity.

The cotton batting was placed on a sheet of aluminum foil inside a laboratory hood. The foam sample was placed on top t he batting and a 4" x 4" ferro plate (12) was placed on top the foam. A one pound weight was placed in the center of the form plate for one minute, after which the weight and ferro plate were removed.

for the cigarette test a king-size non-filter-tipped cigarette (Pall Mall) was lighted, laid diagonally across the 4", x, 4'f foam sample, and allowed to burn completely. Eor... the methenamine tablet test, a tablet was placedinthe center of the foam sample, ignited with a paper match and allowed to burn until consumed or until all visible fla'me had disappeared. The hood was closed with the exhaust fan off during the testing.

After all visible evolution of smoke had ceased from the foam-batting composite, the exhaust fan was turned on'to= removes'moke" and fumes, the hood was oplened and the foam and batting inspectedl visually. Results were as follows: v

" I Cigarette test; foam formulation No. l w I spot on batting at that in color. a %,-No burn through, no visible discoloration of batting over. entire length of cigarette. Cigarette ash light ,gray in color. v

point. Cigarette ash light gray Cigarette test: 'foamformu'lation No. 3' 1/$T'-NO burn through, slight brown discoloration for batting full length of cigarette. Cigarette ash dark gray.

color.

H i Cigarette test: foam formulation No. 4

t"-No burnthrough but black spot at tail end, both on 1 foam and batting.- Cigarette ash dark gray in color. %"--No burn through, light brown discloroation of In none of the above tests was the cotton batting ignited by the glowing cigarette.

Methenamine tablet test: foam formulations Nos. 1 and 2 A"Entire foam sample burned, igniting batting which smoldered to ash. Since battings ignited, second test not run. I

Methenamine tablet test: foam formulation No. 3

/t"About half of foam sample burned, igniting batting as above. (Two tests gave identical results.) 1 %"-Burn area about 2 inch diameter, /e'. deep. Very light brown discoloration of foam on bottom, no discoloration of batting. Foam formed char across top of burn area, pill fell through char and flame extinguished.

Pill not totally consumed.

Methanamine tablet test: foam formulation No. 4

A"Burn area approximately 1 inch diameter. Black char crust on bottom of foam sample. One-half inch diameter black char area on batting but not ignition of batting. (Two tests gave identical results.)

A"Burn area about 1 inch diameter, /2 deep. No discoloration on bottom of foam or on batting. Pill fell through char across burn area and was extinguished before being completely consumed.

(11) Hexamethylene tetraamine, Ely Lilly & Co. Reagent Tablet No. 1588 for timed burning. See, also, The Merck Index, Seventh Edition, Merck & Co., Inc., Rahway, N.J., 1960, page 665.

(12) Steel plate chrome plated on one side.

The results of the cigarette tests shows that Foam No. 4 of the present invention was much better with respect to fire resistance than Foams 1 and 2 and was as good as or better than Foam 3. The results of the methenamine tablet tests showed that Foam No. 4 of the present invention was very much better with respect to fire resistance than Foams 1 and 2 and much better than Foam 3.

EXAMPLE HI A polyetherurethane foam was prepared generally according to the procedures of Examples I and II, above. The formulation of the foam was as follows:

Ingredient: Parts by weight Poly G-3030 PG* 100.0 H O, deionized 2.2 L-540* 8.0 T-9* 0.5 Triethylene diamine 0.2 Polyvinyl chloride resin 20.0 Cercclor 42 a 10.0 Aluminna trihydrate* 50.0 Antimony trioxide* 5.0 Freon 11 1 10.0 Tolylene diisocyanate* 31.5

1 Example 11, above, Formulation No. 4.

=Chlorinated paraffin, liquid, approximate molecular weight of 530, contains about 42% by weight of chlorine, viscosity of about 25 poises at 25 (3., 1.0.1. America, Inc.

*See Example 1, above.

The properties of the resulting foam on testing were as follows:

Density (lbs/ft?) 3.35 Tensile strength (p.s.i.) 10.5 Elongation (percent) 120 Tear strength (p.l.i.) 1.10 Comp. load defl.:

Compression set (percent) (50% Method B) 9.5

12 Flammability. (ASTM D-1692-68) Initial rate ("/min.) 0.80 After heat aging (/min.) (22 hrs. 284 F.) 0.75 Weight loss after heat aging (percent) (22 hrs. V 284 1 0.4

I 1 Self ext. 207 sec. I v Thisexample shows that substantially the same results are obtained when part of the halogen-containing polymer is replaced with a chlorinated paraffin.

' EXAMPLE IV Additional polyetherurethane foams were prepared by the general methods of Examples I to III, above. Polyethcrpolyol masterbatches were prepared as follows:

Masterbatch (parts by weight) Ingredient A B Poly (3-3030 PG 96. 0 96. 0 Alumina trihydrate i 50. 0 50. 0 Polyvinyl chloride resin 20. 0 Polyvinyl chloride resin I 20. 0 I Antimony trioxide 5. 0 5. 0

NOTE-m-FOI' footnotes see Example I.

The other ingredients of the foam formulations were then mixed into the masterbatches in the order and amounts shown below, and the resulting mixtures were allowed to foam.

No'rE.-For footnotes see the following table.

After curing, samples of the foams weretested for flammability (ASTM D-l692-68), and the following results were obtained:

Self ext. Amount of time (sec.) burn, inches Comments Run 1A: Sample 1..- 203 2. Charred and no dripping. Sample 2... 211 2. 75 Do. Run 1B:

Sample 1. 2. 00 Do. Sample 2. 157 1. 88 Do.

1 See Example II, above, Formulation No. 4.

Vygen 3019, The General Tire 6: Rubber Company, intrinsic viscosity of about 1.06, particle size about 98% through a 200 mesh, and 2% retained on a 200 mesh (about 74 microns) screen, suspension polymerized.

l Bee Example III, above.

See Example I, above.

These results show that replacement of part of the halogen-containing polymer with a chlorinated parafiin still gives useful foams having self-extinguishing properties. On the other hand when all of the halogen-containing polymer is replaced with the chlorinated parafiin, the resulting foams exhibit poor cell structure, tend to collapse, show poor charring, and are not self-extinguishing.

EXAMPLE V Additional polyetherurethane foams were prepared by and tested by the method of Run B, Example I, above, in which the parts are parts by weight. In these foams the polyvinyl chloride, alumina trihydrate and/or antimony trioxide wereomitted, except in the control Run No. 28. 0 After curing and cooling, samples were cut from the foams and they weregiven various tests to show their physical properties and resistance to flammability.

The ingredients of the foam formulations and the results obtained on testing-the flexible foams are shown in f -tablebelowz v I.

The method according toclaim 3 in which the resin (I) is polyvinyl chloride. I

' TABLE Run number 21 7 23 r 24 i 25 i 26 27 28 Foam ingredients, parts by weight: j

Poly (3-3030 PG 1 100. 100. 0 100. 0 100. 0 100. 0 100. 0 100. 0 100. 0 H2O (deionized) 2. 2. 2. 5 I. 1 2. 5 2. 5 2. 5' 2. 5 2. 5 L540 -0. 75 0. 75 0. 75 0. 75 D. 75 0. 75 0. 75 0. 75 If-9* 0. 50 0. 50 0. 50 0. 50 0. 50 0. 50-- 0. 50 0. 50 A-l"...- 0. 1 0. l 0. 1 0. 1 0. 1 0. 1 0. 1 0. 1 Polycat 12E 0. 2 0. 2 0. 2 0. 2 0. 2 0. 2 0. 2 0. 2 Marvinol 51 20. 0 20. 0 20. 0 20. 0 Alumina trihydrate 50. 0 50. 0 50. 0 50. 0 Antimony trloxide' 3. 0 3. 0 3. 0 3. 0 Dactol 5. 0 5. 0 5. 0 5. 0 5. 0 5. 0 5. 0 5. 0 D1 36. 0 36. 0 36. 0 36. 0 36. 0 36. 0 36. 0 36. 0 Foam properties, density (lbs/in 2. 34 2. 45 3. 18 2. 2 2.75 3. 55 3. 26 3. 64

Comp. load deflection:

CLD 2 27. 5 22. 5 30. 0 17. 5 23. 8 40. 0 32. 5 42. 5 55. 0 56. 3 73. 8 38. 8 66. 3 104 75. 0 111. 0 OLD R- 21. 3 20. 0 25. 0 13. 8 20. 0 32. 5 26. 3 33. 8 Comp. set (50%, method B), percent 6-5 12- 1 13- 2 31. 8 15. 5 11. 3 11. 7 10. 6 Flammability (ASTM D-1692-68) Burns Bums Bums Burns Burns Burns Burns After heat; aging (22 hrs. at 284 F.) Burns Bums Burns Burns Burns Burns Burns Weight loss after heat aging (percent) (22 hrs. at 284 F.) 0. 5 0. 5 0. 37 0. 51 0. 4 0. 34 0. 37 0. 37 Tensile strength (p s.i 12. 7 12. 7 10. 3 10. 0 l0. 0 11. 3 10. 7 11. 7 Elongation (percent) 170 120 123 140 103 90 107 83 T r strength (p,l,i,) 1. 70 1. 70 1. 55 1. 75 1. 80 1. 68 1. 77 1. 70

I\ Sell extinguishing time 175 seconds. Self extinguishing time 126 seconds.

The same as Example I, above.

The above data clearly show the improvement in flame resistance imparted to polyurethane foams containing a halogen-containing resin, antimony trioxide and alumina trihydrate. Other foams similarly prepared but omitting one or more of the ingredients such as the polyvinyl chloride, alumina trihydrate and/or the antimony trioxide burned; for example, they did not exhibit any self-extinguishing properties, when tested according to the foregoing test.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. 1n the method of making a flame retardant flexible or semiflexible low density, polyurethane foam by the reaction of (A) a polyetherpolyol having from two to four hydroxyl groups and having a molecular weight of from about 1000 to 10,000, (B) an organic polyisocyanate and (C) a blowing agent comprising water in the admixture with (D) a surfactant and (E) a catalyst, using the oneshot or prepolymer process, the improvement comprising incorporating in said formulation as essential flame retardant additives (I) from about 2 to 100 parts by weight per 100 parts by weight of said polyol of a finely divided, solid halogen-containing polymeric resin having an intrinsic viscosity of from about 0.25 to 2.5, (II) finely divided alumina trihydrate in an amount of from about to 80 parts by weight per 100 parts by weight of said polyol, and (III) finely divided antimony trioxide in an amount of from about 1 to 20 parts by weight per 100 parts by weight of said polyol.

2. The method according to claim 1 in which the polyol A is a polyalkylene ether polyol, the catalyst comprises a tertiary amine in an amount of from 0.05 to 0.9 part by weight per 100 parts by weight of said polyol and from about 0.1 to 0.9 part by weight per 100 parts by weight of said polyol of a metal-containing polyurethane catalyst.

3. The method according to claim 2 in which the resin (I) is selected from the group consisting of polyvinyl chloride, a copolymer of a major amount of vinyl chloride and a minor amount of vinyl acetate, a partially hydrolyzed copolymer of a major amount of vinyl chloride and a minor amount of vinyl acetate, and chlorinated polyethylene and in which said resin is used in an amount of from about 5 to 50 parts by weight, the alumina trihydrate (II) is used in an amount of from about 45 to 75 parts by weight and the antimony trioxide (III) is used in an amount of from about 3 to 15 parts by weight, the amounts of said (I), (II) and (III) being based on 100 parts by weight of said polyol.

5. The method according to claim 4 in which the metalcontaining catalyst is stannous octoate.

6. The method according to claim 1 wherein from about 5 to 70% by weight of a chlorinated paraflin is used to replace an equal amount by weight of said halogen containing polymeric resin (I), staid chlorinated paraflin having an average molecular weight of from about 250 to 1400 and containing from about 40 to 70% by weight of chlorine.

7. A flame retardant low density, flexible or semiflexible polyetherurethane foam, the ether moieties of said foam being derived from polyols having a molecular weight'of from about 1,000 to 10,000 and from 2 to 4 hydroxyl groups containing as essential flame retardant additives, based on 100 parts by weight of said polyol, (I) from about 2 to 100 parts by weight of a finely divided, solid halogen-containing polymeric resin having an intrinsic viscosity of from about 0.25 to 2.5, (II) finely divided alumina trihydrate in an amount of from about 30 to parts by weight, and (III) finely divided antimony trioxide in an amount of from about 1 to 20 parts by weight.

8. A foam according to claim 7 in which the polyol is a polyalkylene ether polyol and the catalyst includes, based on parts by weight of said polyol, a tertiary amine present in an amount of from about 0.05 to 0.9 part by weight and a metal-containing polyurethane catalyst present in an amount from about 0.1 to 0.9 part by weight.

9. A foam according to claim 8 in which the resin (I) is selected from the group consisting of polyvinyl chloride, a copolymer of a major amount of vinyl chloride and a minor amount of vinyl acetate, a partially hydrolyzed copolymer of a major amount of vinyl chloride and a minor amount of vinyl acetate, and. chlorinated polyethylene and in which said resin is present in an amount of from about 5 to 50 parts by weight, the alumina trihydrate (II) is present in an amount of from about 45 to 75 parts by weight, and the antimony trioxide (III) is used in an amount of from about 3 to 15 parts by weight, the amounts of said (I), (II) and (III) being based on 100 parts by weight of said polyol.

10. A foam according to claim 9 in which the resin (I) is polyvinyl chloride.

11. A foam according to claim 10 in which the metalcontaining catalyst is stannous octoate.

12. A foam according to claim 7 wherein from about 5 to 70% by weight of a chlorinated paraflin is used in 2. 5 :16 p ac -;anr. s. mw t bnwei hi eq sais tha fi 1 Re s C d;v containing polymeric resin (I), saidt-chlorinated parafiin 1 ,VuUNI-TED .STATESLPATENTS having an average molecular weight of from about 250 3,574,149 4/1971 Harrington to 1400 and containing from about 40 to 70% by weight 3,075 923 1 1953 Lanham ofchlorinei assailawlrlinm. 4 5 i v {fjreen H V v H I foarmaccordingto -claim' nnated parafiinis a liquld.

(5/69) a h M a @rrnhf Patent No. 3, j 5 hheea May 1M, 197A I t Arthur J. Norman and David S. Cobblediok It is certified that error appeara in "the a'tove idehtified patent and that said Letters Patent are hereby wrrected as shown below:

Coluirn t, lines" 16-17, which reads: d:L aorop3/*lene glycol,

trimethylolpropane, should read ----dipropylene glycol glycerol, trimethylolpropane, h

Column 7, line 31 which reads: foam should read ---foams---.

Column n which reads: "were omitted." should read --Was omitted" Columns 7 a 8 (Table), which reads: "wei ht loss after heat aging (percent) (22 hrs at 28 +F.)--3..O" should read ----Wei ght loss after heat aging (percent) Signed and sealed this 2 mb day of Deczember 1974.

- (SEAL) 6 Attest:

McCOY Mw GIBSON JRo C;o Z-LhRSI-IAlL DAWN attesting Officer Gemiasioner of Patents 

